Motorola presented a National Quality Day segment several years ago where they discussed “Half Way to the Wall.” It is a pretty neat concept that doesn’t seem to have become cliché, but possibly should.
Summarizing- Initial targets for quality are established by determining current baselines and then cutting the defect rate in half. If you are currently 50% good at something the idea is to move this up to 75%. A 75% you go for 87.5% good. There are several neat points to this system:
1) Fact-Based Decision Making is required. It is cliché to say you can’t make good decisions with bad information. The challenge in this age of TMI (too much information) is deciding what you really need to know and then gathering the information accurately;
2) Initial Gains are relatively much easier than later gains. It is as easy (or easier) to move from 80% to 90% than it is to move from 90% to 95%. The next step to 97.5% is even more challenging. Once defect rates become very low the challenge in keeping them good is not only not slipping back to old ways, but also not allowing new defects to creep in.
3) Marginal Utility (aka Law of Diminishing Returns) also comes into play at a point. The question “at what price success?” has value. The cost of training, test equipment, inspectors or other cures necessary to make small incremental gains just might not be worth it.
These concepts can be and are actively applied to liquid cylinder repairs by West Cryogenics and our clients. One of the most valuable tools used is the ability West has to monitor incoming vacuum levels on previously repaired liquid cylinders. Active use of this information allows for identification of potential issues so we can work together with clients to find root causes and affect solutions. A large percentage of cylinders returned with good vacuums can indicate operational or training issues at the client side. A rise from 2% to 8% “bad vacs” could indicate an issue at the supplier or user side.
One case found that a client’s cylinders were being exposed to excessive levels of cleaning chemicals resulting in high corrosion. Another found that liquid cylinders were too close to a welding or cutting procedure. Sparks from the procedure were melting tiny holes in vacuum rupture disks.
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